1. Field of the Invention
The present invention relates to a sound generating apparatus, a sound generating space, a sound, and a method for generating a sound, and in particular, a sound generating apparatus, a sound generating space, a sound, a method for generating a sound, each provided for significantly increasing cerebral blood flows of a person.
2. Description of the Prior Art
It is generally accepted that audio frequencies above 20 kHz do not affect human sensory perception since they are beyond the audible range. Due to this, the sampling frequency for compact discs (CDs) and mini discs (MDs) is set to 44.1 kHz, and the equipments for these discs are manufactured so that audio signals up to about 22 kHz can be recorded and reproduced. Also, the sampling frequency for digital audio tape recorders (DATs) as well as digital compact cassette recorders (DCCs) can be set to any one of the frequencies, 48 kHz, 44.1 kHz, and 32 kHz, and the equipments for these are manufactured so that audio signals up to about 24 kHz can be recorded and reproduced. Thus, generally, human being is allowed to relax himself or herself by listening to favorite music with the use of these equipments.
On the other hand, the strength of α-EEG (α-electroencephalogram) or α wave generated from the human brain is generally used as an index indicating that one has less stress. Taking advantage of the fact that when a ultra-low frequency signal of around 10 Hz is generated and heard or listened to, one will generate α-EEG, there have been developed and marketed apparatuses for generating such an ultra-low frequency signal.
However, in the above-mentioned prior art, there are such problems that, the degree to which stresses can be relieved would change depending on the contents of the music or the frequencies of the ultra-low frequency signal, and moreover the degree thereto would be relatively small.